Scott B. answered • 07/17/21
PhD research director with 10+ years chemistry tutoring experience
Gases follow the ideal gas law pv=nRT where p is pressure, v is volume, n is the number of moles of gas, R is the ideal gas constant and T is temperature.
If you rearrange to try to solve for temperature you get T=pv/nR. In your problem, we assume that p and n don't change and R is always a constant. Therefore, you can essentially drop all those parameters and and that leaves us with the change in temperature being directly proportional to the change in volume.
So you can use Charles's Law which is V1/T1 = V2/T2.
If we rearrange to solve for temperature, we get T2 = V2 X T2/V1
From here you can just plug in your values. The only thing to remember is volume is in liters, but temperature in Kelvin, so you have to convert by adding 273 to the Celsius temperature (45+273 = 318)
T2 = 0.95 X 318 / 1.3
T2 = 232.4 K or (-40.6 C) is the temperature where the volume of gas will be 0.95
